Transfroming applied tractions into statically equivalent nodal force BC

Hello,

I am trying to produce results for problems with analytical solution to validate my FE code. One of the problmes is the classical plate with a hole configuration with tractions applied at boundaries. However, presently, I can only impose BC in terms of nodal forces and displacements. Therefore I must transform the applied stress in statically equivalent nodal forces.

This has lead me to wonder about general mathematical formulation which can be used to transform any arbitrary traction into statically equivalent nodal forces. Can somebody please elaborate on the procedure or point me to a relevant source which would be useful?

Thank you.

-Mithil